This invention relates generally to wireless communications circuitry, and more particularly, to antenna circuitry for electronic devices such as handheld electronic devices.
Handheld electronic devices are becoming increasingly popular. Examples of handheld devices include handheld computers, cellular telephones, media players, and hybrid devices that include the functionality of multiple devices of this type.
Due in part to their mobile nature, handheld electronic devices are often provided with wireless communications capabilities. Handheld electronic devices may use long-range wireless communications to communicate with wireless base stations. Handheld electronic devices may also use short-range wireless communications links. For example, handheld electronic devices may communicate using the WiFi® (IEEE 802.11) bands at 2.4 GHz and 5 GHz and the Bluetooth® band at 2.4 GHz. Communications are also possible in other bands.
To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to reduce the size of components that are used in these devices. For example, manufacturers have made attempts to miniaturize the antennas used in handheld electronic devices.
A typical antenna may be fabricated by patterning a metal layer on a circuit board substrate or by patterning a sheet of thin metal using a foil stamping process. Antennas such as planar inverted-F antennas (PIFAs) and antennas based on L-shaped resonating elements can be fabricated in this way. Antennas may also be formed using flexible printed circuit substrates.
Although modern handheld electronic devices often need antennas with precisely defined radio-frequency responses, manufacturing variations and unexpected design changes can lead to situations in which an antenna is detuned somewhat from its optimal frequency response. These manufacturing variations may arise due to variations in the flexible printed circuit substrates that are used in forming the antennas. For example, antenna performance variations can arise when flex circuit substrates are produced by different manufacturers and are therefore not all identical.
It would therefore be desirable to be able to provide improved antennas and wireless handheld electronic devices.